<!DOCTYPE html>
<html>

	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			.left {
				width: 300px;
				background-color: red;
				float: left;
			}
			
			.right {
				width: 200px;
				background-color: blue;
				float: right;
			}
			
			.center {
				background-color: green;
				margin: 0 200px 0 300px;
			}
			
			div {
				height: 300px;
			}
			
			.inner {
				width: 50px;
				height: 50px;
				background-color: #fff;
			}
		</style>
	</head>

	<body>

		<div class="left"></div>
		<div class="right"></div>
		<div class="center"></div>
		<p class="inner"></p>

	</body>

</html>